The Codice 15 is one of the most valuable and unknown sources in the Treviso Cathedral Archive. This choirbook was copied in 1569. It contains eight anonymous Magnificats, one for each tone, copied along 47 folios. In the index only the title Magnificat a 5 can be read.
All the Magnificats are for second vespers: they set in polyphony the even verses of the Magnificat, leaving the odd verses to be sung in plainchant. Although the index indicates that these eight Magnificats are for five voices, only the Magnificat Septimi toni ends with five voices. The other six Magnificats end with six voices, except Magnificat sexti toni, finishing with eight voices.